The invention is a manifold assembly and the method of making it. One use of the manifold assembly is to control the height of a truck""s seat. The manifold assembly may be used in many other instances where small solenoids are employed in the manifold assembly.
Small solenoids produce small plunger forces. Small solenoids may be used in a manifold where low forces are applied to the plungers or to plunger seals attached to the plungers. Pressure applied to a surface area results in a force on that surface. Therefore, it is desirable in the design of manifolds to minimize the area of the plunger seal upon which pressure is applied. Plunger seals attached to solenoid plungers are used to control the flow of gas or other fluid through orifices (having cross-sectional areas) in manifolds.
Manifolds are generally molded in one piece and usually require machining. One piece molded manifolds require a longitudinal pin and multiple transverse pins to be used as part of the mold. The transverse pins are attached to the longitudinal pins and it is these transverse pins which form the passageways and orifices in the manifold through which fluid/gas flows. Small orifices are closed with small plunger seals having small surface areas. Since pressure is applied to these small plunger seal surface areas, the operators (i.e., solenoids) driving the plunger seals do not have to be very large to resist the forces applied to the plunger seals. Pins in a one piece mold are difficult to positionally control and they can be damaged by the incoming polymeric material which is injected under high pressure and high velocity.
The instant invention solves the aforementioned problems.
A manifold assembly is disclosed having two portions, a manifold portion and a plug portion ultrasonically welded together. Sometimes herein just the word manifold may be used to denote the manifold assembly. A multiple piece mold is used to form the manifold portion such that small orifices and passageways are formed which are subject to process pressure. By reducing the cross-sectional area of the orifices, forces on the plunger seals attached to solenoid plungers are reduced enabling the use of smaller operators (i.e. solenoids).
The manifold assembly comprises a body having an inlet port, an inlet housing, a supply port, an exhaust housing, and a chamber. The chamber interconnects the inlet housing, the supply port, and the exhaust housing. The inlet port is interconnected by a first passageway with the inlet housing. The inlet housing is interconnected by a second passageway to the chamber. The exhaust port is also interconnected by a third passageway to the chamber. The exhaust port is interconnected by a fourth passageway to the atmosphere external to the manifold. The chamber is formed by a plug portion ultrasonically welded to the manifold portion of the manifold assembly.
An inlet solenoid with a first plunger seal resides in the inlet housing and an exhaust solenoid with a second plunger seal resides in the exhaust housing. The inlet housing includes a first valve seat and the exhaust housing includes a second valve seat. The first plunger seal acts and seals against the first valve seat. The second plunger seal acts and seals against the second valve seat. The second passageway interconnects the chamber and the inlet housing and a third passageway interconnects the chamber and the exhaust housing.
A first tube connector is affixed to the inlet port and a second tube connector is affixed to the supply port. The tube connectors are inserted in the manifold portion prior to the complete cooling of the manifold portion after it is removed from the mold. This enables easy assembly of the tubes to the manifold. The supply port supplies air or other fluid to a reservoir. When air or other fluid is removed from the reservoir, it flows through the supply port and through the chamber, through the third passageway, through the exhaust housing past the second valve and through the fourth passageway to atmosphere. Preferably the manifold body and the plug are made from an acetal resin sold under the trademark Delrin(copyright) which is registered to E. I. DuPont de Nemours.
Preferably each of the aforementioned second and fourth passageways have a length to diameter ratio less than 4. Specifically it is desired that the length-diameter ratio of each of the second and fourth passageways between the inlet housing and the chamber and between the exhaust housing and the exterior of the manifold be less than 4.
The inlet housing and the exhaust housing each include a valve seat. Concentric with these valve seats are the aforementioned second and fourth passageways. These passageways have a small diameter which enables the use of a small solenoid in the respective housings. A small solenoid may be used because the pressures are applied to a small plunger seal area resulting in a relatively small force which must be overcome by the respective solenoid. The small diameter passageways and orifices are made by a process for making the manifold portion.
The manifold assembly is manufactured from two parts, a manifold portion and a plug portion ultrasonically welded together. A multiple piece mold is employed to make the manifold portion of the manifold assembly.
A bottom mold portion, a top mold portion, a first rotatable mold portion, a second rotatable mold portion, an inlet mold portion, a right slide portion, and a left slide portion are secured together and form a cavity therein. The bottom mold portion and the top mold portion are in contact in one place. The bottom mold portion contacts the first rotatable mold portion forming: (1) the first passageway interconnecting the inlet port and the inlet housing; and, (2) a second passageway interconnecting the inlet housing and the chamber. The bottom mold portion contacts the second rotatable mold portion forming: (1) the third passageway interconnecting the chamber and the exhaust housing; and, (2) a fourth passageway interconnecting the exhaust housing and the atmosphere external to the manifold. Once the mold is secured together a polymer is injected into the cavity. The polymer, once injected, is then allowed to partially cool. The rotatable mold portions are removed by rotating them and then the top portion of the mold is removed. The rotatable mold portions must be rotated because threads are formed in the inlet housing and exhaust housing therearound during the molding process. The right and left slide portions separate. The top and bottom portions of the mold are then removed.
While the injected polymer is still very warm and has not yet taken its final room temperature size and shape, the plug portion is ultrasonically welded to the manifold portion enclosing the chamber which creates the manifold assembly.
It is an object of the present invention to provide a manifold assembly having valve seats in solenoid housings with concentric passageways therethrough having small diameters.
It is a further object of the present invention to provide a manifold assembly having eccentric passageways connecting into or out of the solenoid housing cavities.
It is a further object of the present invention to provide a manifold assembly manufactured by ultrasonically welding two pieces together, a manifold portion and a plug portion.
It is a further object of the present invention to provide a manifold assembly having at least one tube connector secured therein.
It is a further object of the present invention to provide a manifold assembly having at least one barbed end connector integral therewith.
It is a further object of the present invention to provide a manifold assembly which uses small, low power solenoids for closing orifices in the manifold.
It is a further object of the present invention to provide a manifold assembly which employs passageways having a length to diameter ratio less than or equal to 4.
Further objects of the invention will be understood when reference is made to the Brief Description of the Drawings, the Description of the Invention, and the Claims which follow hereinbelow.